[libc] [libcxx] [lld] [clang] [llvm] [compiler-rt] [flang] Fix ISel crash when lowering BUILD_VECTOR (PR #73186)

[David Li via cfe-commits]

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@@ -986,15 +1003,15 @@ void X86DAGToDAGISel::PreprocessISelDAG() {
     case X86ISD::VBROADCAST: {
       MVT VT = N->getSimpleValueType(0);
       // Emulate v32i16/v64i8 broadcast without BWI.
-      if (!Subtarget->hasBWI() && (VT == MVT::v32i16 || VT == MVT::v64i8)) {
-        MVT NarrowVT = VT == MVT::v32i16 ? MVT::v16i16 : MVT::v32i8;
+      if (!Subtarget->hasBWI() && needBWI(VT)) {
+        MVT NarrowVT = getNarrowType(VT);
         SDLoc dl(N);
         SDValue NarrowBCast =
             CurDAG->getNode(X86ISD::VBROADCAST, dl, NarrowVT, N->getOperand(0));
         SDValue Res =
             CurDAG->getNode(ISD::INSERT_SUBVECTOR, dl, VT, CurDAG->getUNDEF(VT),
                             NarrowBCast, CurDAG->getIntPtrConstant(0, dl));
-        unsigned Index = VT == MVT::v32i16 ? 16 : 32;
+        unsigned Index = getInsertIndex(VT);
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david-xl wrote:

Comments addressed. PTAL

https://github.com/llvm/llvm-project/pull/73186